As is known in the art of door latching, typically an electrically-controlled strike is mounted in a frame portion of a door and engages a mortise-type lockset disposed on or in an edge portion of the door. Typically, the mortise-type lockset includes a spring latch and a dead latch that is linearly spaced-apart from the spring latch along the edge portion of the door. The spring latch is reciprocally moveable between an engaged position so that it can engage an entry chamber in the strike, thereby to secure the door in a closed state, and a released position, wherein the door is released from the closed state and is free to open. The dead latch is reciprocally moveable between an enabling position (extended) that permits movement of the spring latch from its engaged position to the released position and a disabling position (depressed) that prohibits movement of the spring latch from its engaged position to its release position. The spring latch is resiliently biased into an engaged position and the dead latch is resiliently biased into the enabled position. (When the dead latch is in the enabled, extended position, the spring latch is able to be depressed from its engaged position).
U.S. Pat. No. 6,581,991 B2, the relevant disclosure of which is incorporated herein by reference, discloses an electrically-controlled strike comprising a housing adapted to be mounted in a frame portion of a door and having a cavity with a forwardly disposed opening that is sized and adapted to receive a spring latch and a dead latch when the door is in the closed state. The invention provides a single electrically actuated door latch structure that can be customized to a variety of spring latch and dead latch arrangements.
U.S. patent application Ser. No. 12/851,848, filed Aug. 6, 2010 and assigned to Hanchett Entry Systems, Inc. discloses an improved door strike having a spring latch kicker and a dead latch release platform which can be adjusted to various positions in conjunction with the specific mortise lockset used. A rectangular housing is disposable within the frame of a door pivotably mounted in the frame. The housing includes an elongate opening defining an entry chamber for a spring latch and a dead latch of a mortise lockset in the door. An entrance ramp for the spring latch and dead latch extends from an edge of the housing. A keeper is pivotably mounted within the chamber to selectively engage and retain the spring latch. A kicker is also pivotably mounted within the chamber and is interlocked with the keeper and engageable by the spring latch. A dead latch release platform is also pivotably mounted within the chamber and is supported at an opposite end by the keeper when the spring latch is secured within the strike. When a release command is received, the keeper is allowed by means of an actuator, such as a solenoid, to rotate and then rotates, from a door-opening force, against the force of its return spring into a position from which the spring latch may be ramped out of the strike opening. The keeper rotation allows the dead latch release platform to pivot into the cavity against the force of a release platform return spring, thereby releasing the dead latch to be extended into the cavity which allows the spring latch to be ramped out as it is depressed into the door. The pivot action of the keeper and a leg of the keeper acting directly on the kicker causes the kicker to engage the nose of the spring latch and to boost the spring latch onto a ramp surface formed on a face of the keeper. The spring latch then leaves the kicker, climbs the ramp surface and exits the strike as the door opens in the frame. After the spring latch has cleared the strike, the keeper rotates to its lock position under the force of its return spring, the dead latch release platform returns to a position supported by the keeper under the force of its return spring so that the dead latch is held in its depressed position by the supported dead latch release platform upon closing the door.
The dead latch release platform can be installed in any of a plurality of different vertical (along the long dimension of the housing) locations in the housing opening to accommodate any of a plurality of different lockset arrangements.
What is needed in the art is an electrically-controlled strike wherein the dead latch release platform is positively driven by the keeper to its return position in preparation for relatching of a door.
What is further needed is a strike wherein a spring latch lifter feature includes (1) a pivotable member that is driven by the keeper to positively and continuously push the spring latch onto the exit ramp during unlatching of the door, or (2) an internal ramp to form a continuous incline whose surface aligns with a ramped nose of the keeper and an external ramp to lift the spring latch out of the entry chamber when the keeper releases the spring latch and the door is moved in an opening direction.
It is a principal object of the present invention to reduce the cost and complexity of an electrically-controlled strike for a door with a mortise lockset and to improve reliability of operation.